I have a Cintiq 12WX and while I love (LOVE) using it in photoshop, I still use my intuos for zbrush. There just isn't enough space on the screen to use zbrush effectively in my experience. I find that while Zbrush is definitely best used with a tablet, it also needs to be on a large monitor. I would save for the 21 or…
I use a 21 at work and just ordered myself a 21 that will be with me in a few weeks. To me, it's seriously a life changer. I find it hard to go back to using 'just' a tablet. I don't really notice the lag most people complain about, either because I use lazymouse a bunch or because I would rather that than the disconnect…